#!/usr/bin/env bash
#
# Build a macOS .dmg from a .app bundle.
#
#   hack/make-dmg.sh <App.app> <volume name> <out.dmg>
#
# On macOS this uses hdiutil. On Linux it uses hfsprogs + hfsplus to create an
# HFS+ image and mozilla/libdmg-hfsplus (`dmg build`) to convert it to UDIF;
# both are installed in the builder image.
#
# The Linux image is functional (the app plus an /Applications symlink) but
# has no Finder background or icon placement: those live in a .DS_Store
# generated by hdiutil, which is macOS-only.
set -euo pipefail

if [ "$#" -ne 3 ]; then
  echo "usage: $0 <App.app> <volume name> <out.dmg>" >&2
  exit 2
fi

APP="$1"
VOLUME="$2"
OUT="$3"

if [ ! -d "$APP" ]; then
  echo "$APP is not a directory" >&2
  exit 1
fi

TMP="$(mktemp -d "${TMPDIR:-/tmp}/streamplace-dmg.XXXXXX")"
trap 'rm -rf "$TMP"' EXIT

ROOT="$TMP/root"
mkdir -p "$ROOT"
# -a preserves the nested framework symlinks and executable modes; the code
# signature is embedded in the Mach-O files, so nothing else needs carrying.
cp -a "$APP" "$ROOT/"
ln -s /Applications "$ROOT/Applications"

mkdir -p "$(dirname "$OUT")"
rm -f "$OUT"

if command -v hdiutil >/dev/null; then
  hdiutil create \
    -volname "$VOLUME" \
    -srcfolder "$ROOT" \
    -ov \
    -format UDZO \
    "$OUT" >/dev/null
  exit 0
fi

for tool in mkfs.hfsplus hfsplus dmg; do
  if ! command -v "$tool" >/dev/null; then
    echo "$tool not found; the builder image is stale (recreate the container" >&2
    echo "after .ci/dockerfile-hash.yaml changes) or this is not the container." >&2
    exit 1
  fi
done

USED_KB="$(du -sk "$ROOT" | cut -f1)"
SIZE_MB=$(( USED_KB / 1024 + 64 ))

dd if=/dev/zero of="$TMP/image.img" bs=1M count="$SIZE_MB" status=none
mkfs.hfsplus -v "$VOLUME" "$TMP/image.img" >/dev/null
hfsplus "$TMP/image.img" addall "$ROOT" -s clone_link >/dev/null
dmg build "$TMP/image.img" "$OUT" >/dev/null